How Lethal Injection Works

Inside the execution chamber at North Carolina's Central Prison, where lethal injection is on hold because of the argument about whether a physician involved in theprocedure breaks the Hippocratic oath

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Unless a call is received from state officials to stay the execution, the execution proceeds as planned. While a lethal-injection machine exists, and was once used by several states, most states now opt to perform the injections manually due to the fear of mechanical failure. Usually an execution team comprises prison employees. Some states use the same personnel for every execution, while others rotate the duty among several employees.

The execution team is either in a separate room or behind a curtain and cannot be seen by witnesses or the condemned. In some cases, the executioners may wear a hood to conceal their identity. At the warden's signal, the execution team will begin injecting lethal doses of two or three drugs into the IVs. Some states use multiple executioners, all of whom inject drugs into an IV tube -- but only one of the executioners is actually delivering the lethal injection. None of the executioners know who has delivered the lethal dose and who has injected drugs into a dummy bag.

The drugs are administered, in this order:

Anesthetic - Sodium thiopental, which has the trademark name Pentothal, puts the inmate into a deep sleep. This drug is a barbiturate that induces general anesthesia when administered intravenously. It can reach effective clinical concentrations in the brain within 30 seconds, according to an Amnesty International report. For surgical operations, patients are given a dose of 100 to 150 milligrams over a period of 10 to 15 seconds. For executions, as many as 5 grams (5,000 mg) of Pentothal may be administered. This in itself is a lethal dose. It's believed by some that after this anesthetic is delivered, the inmate doesn't feel anything.

Saline solution flushes the intravenous line.

Paralyzing agent - Pancuronium bromide, also known as Pavulon, is a muscle relaxant that is given in a dose that stops breathing by paralyzing the diaphragm and lungs. Conventionally, this drug takes effect in one to three minutes after being injected. In many states, this drug is given in doses of up to 100 milligrams, a much higher dose than is used in surgical operations -- usually 40 to 100 micrograms per one kilogram of body weight. Other chemicals that can be used as a paralyzing agent include tubocurarine chloride and succinylcholine chloride.

Saline solution flushes the intravenous line.

Toxic agent (not used by all states) - Potassium chloride is given at a lethal dose in order to interrupt the electrical signaling essential to heart functions. This induces cardiac arrest.

Within a minute or two after the last drug is administered, a physician or medical technician declares the inmate dead. The amount of time between when the prisoner leaves the holding cell and when he or she is declared dead may be just 30 minutes. Death usually occurs anywhere from five to 18 minutes after the execution order is given. After the execution, the body is placed in a body bag and taken to medical examiner, who may perform an autopsy. It is then either claimed by the inmate's family or interred by the state.